Embryos in eggs move to get comfy

Even before hatching, some reptiles and birds can shift toward favorable

SMART BLOB Embryos may not look as if they can do much, but new tests suggest that a lot of unfinished creatures, such as this unhatched chicken, can regulate their temperatures by moving to warmer or cooler zones of eggs.

Teng Li

The power to cuddle up to warmth or cringe away from overheating may be widespread among reptile and bird embryos still in the egg, researchers say.

Earlier studies found two species of turtle embryos moving toward warmth or away from dangerously high heat (SN: 6/18/11, p. 9). Now tests of 12 diverse species find active repositioning, says ecologist Wei-Guo Du of the Chinese Academy of Sciences in Beijing.

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